Identification, characterization and modulation of protein-protein interactions using modified peptides

Proteins are one of the key players in organisms and are involved in all cellular processes. They do not perform their functions individually but act in a highly organized, cell-wide interaction network that is governed by protein-protein interactions (PPIs). To explore and characterize these PPIs, the use of peptides in research is essential. They mimic regions of interest in potential binding partners and can be chemically modified to be used in biochemical assays. Furthermore, peptides are used for the modulation of PPIs. Here, modifications are made to regain the bioactive conformation that is often lost when peptides are excised from the stabilizing tertiary protein structure. A way to obtain the bioactive conformation is by structural constraints resulting from e.g. inter-side chain crosslinking. In this thesis, modified peptides are utilized as tools for detection as well as biochemical and structural characterization of PPIs. Further, this thesis presents structural constrained peptides as modulators for PPIs and the detailed characterization of their interaction with the target protein.